Feature gate: #![feature(assert_matches)]

This is a tracking issue for the assert_matches!() and debug_assert_matches!() macros.

Public API

// core

macro_rules! assert_matches { .. }
macro_rules! debug_assert_matches { .. }

Steps / History

• Implementation: Add assert_matches macro. #82770
• Temporarily move the macro into std::assert_matches::assert_matches to avoid breakage: Is there a gentler way to land the assert_matches macro? #82913
• Final commenting period (FCP)
• Stabilization PR
  • Update the must_use message on is_none (per Add messages to Option's and Result's must_use annotation for is_* #62431 (review))
  • Mention this macro in the documentation of matches!()

Unresolved Questions

• Add => expr syntax?
  • Nope, too confusing. (See discussion below.)